Many European countries have different tax rates for food and non-food items purchased. For example, Austria charges 10% for food items and 20% for non-food items. Germany, however, has 7% for food and 19% for non-food with an additional rule that if you buy both food and non-food items, the food items now get 19% applied instead of 7%.
So I'm building a checkout flow for both of these countries as sites and I've set up my tax rates, categories, and zones. Commerce out of the box allows me to designate food and non-food rates, but if I'm on the German site, I need to check to see if the user adds any non-food items along with their food items, and if so, apply the non-food tax to the food items. How can I do this?